1. Field of the Invention
The present invention relate to a flash memory device, and more particularly, a high-voltage switching circuit for a flash memory device and a pumping circuit for the high-voltage switching circuit.
2. Discussion of Related Art
Flash memory devices are nonvolatile memory devices for performing a program operation and an erase operation. In the program operation and the erase operation, a high level voltage is used in the flash memory devices. In general, to this end a switching device is equipped to transmit a high level voltage in a flash memory device.
The conventional switching device generally includes a switching metal-oxide semiconductor (MOS) transistor and a pumping MOS transistor. The switching MOS transistor is gated by a select signal and configured to transmit a high level voltage. Also, the pumping MOS transistor operates as a pumping capacitor, and is configured to increase a voltage level of the select signal through a pumping operation.
Therefore, it is desired that a switching device is capable of increasing a capacitance of the pumping capacitor to increase a voltage level of the select signal. Further, since a layout area of the switching device is apt to increase as the capacitance increases, a need exists for a switching device for a flash memory which is able to minimize the increase of or even no or little increase in the layout area of the switching device while increasing the capacitance.